The disclosure relates generally to a digitally adjustable focused beam lighting system.
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present techniques, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
In the motion picture and television industries, one of the most popular lighting instruments used is a focused beam light known as a “hard light.” Some lighting systems use a Fresnel glass optic combined with a tungsten bulb light source. The beam angle of “Fresnel” lights is typically user adjustable from 15 to 50 degrees. The adjustment is performed by turning a mechanical actuator that changes the focal distance between the lens and the Fresnel optic by moving either the light source or the lens. In many instances, this requires the operator to be able to physically adjust mechanical controls to change the beam angle. This can be quite problematic, as many installations are elevated in a lighting system above a stage, making access of the mechanical actuator problematic.
Another limitation of these traditional Fresnel lights is the light source. Traditional systems have included carbon arcs, tungsten light bulbs, and hydrargyrum medium-arc iodide (“HMI”) light bulbs. The carbon arcs are very temperamental, require significant maintenance, consume significant power, and generate large amounts of ozone. Tungsten bulbs have a low lifespan (e.g., a 500-hour life). When Fresnel lights near the end of their lifespan, the lights may exhibit a shift in color which could lead to unfavorable lighting. Further, 95% of the energy is wasted on heat, and they can only emit one color-correlated temperature (“CCT”) of light—3,200K. HMI bulbs were developed to provide a 5,600K light source which is commonly needed in motion pictures to simulate outdoor light. These lights bulbs have a similar 500-hour lifetime and are also not CCT adjustable. As a result, studios typically stock two completely different types of Fresnel lights, HMI and tungsten, in order to support the two commonly used color temperatures for motion picture and television. Like the original Fresnel lights, both HMI and tungsten lights utilize manual beam angle adjustment while providing increased power. For example, HMI lights come in sizes up to 18,000 Watts. This provides an extreme amount of light that allows film makers to simulate a hard, bright light source like the sun.
Light-emitting diode (“LED”) technology has been introduced that uses similar Fresnel optics. However, the LED replacements require more conservative operating temperatures to keep from damaging the LEDs. LED light sources are also much larger than their tungsten and HMI bulb counterparts. The results are LED Fresnel lights that are high cost but very low power ( 1/10 or less) compared to traditional tungsten and HMI Fresnel lights.
Further, color adjustable LED Fresnel lights have also been introduced. These further reduce the power, because the LED light size needed is larger when it contains a variety of different color LEDs used for color blending. These LED Fresnel lights also use manual beam control adjustment similar to traditional systems.
Another focused beam technology is a HMI parabolic reflector. This light replaces the Fresnel optic lens with a parabolic reflector. Parabolic reflectors offer higher optical efficiency and lower weight than their glass lens, Fresnel counterparts. Parabolic reflector technology is used in lights in many industries. However, such lights with parabolic reflectors face the same limitations described above of a low bulb lifetime, static CCT, and manual adjustment-based change of beam angle.